Unit 1- Metabolism

Question 1

What happens without metabolism?

Answer 1

Absorbed compounds retained longer, prolonged drug activity, tissue drug accumulation, potential toxicity

Question 2

Major organ for drug transformation

Answer 2

Hepatic biotransformation and biliary excretion

Question 3

Factors affecting liver metabolism

Answer 3

Biological properties and enzymes present, hepatic perfusion, drug accessibility to hepatic metabolic sites, physiochemical properties of the drug

Question 4

Phase I Hepatic Metabolism

Answer 4

Makes lipid soluble drugs more water soluble, can inactivate, activate, or change toxicity

Question 5

Phase II Hepatic Metabolism

Answer 5

Inactivates drugs

Question 6

Other metabolic organs

Answer 6

Kidney, lungs, skin, GI

Question 7

Cytochrome P450 Enzymes

Answer 7

Located in smooth ER, adds oxygen onto the substrate

Question 8

Oxidation

Answer 8

Addition of oxygen across a double bond or to a carbon chain, causing loss of an electron

Question 9

Hydrolysis

Answer 9

Splitting a drug molecule and adding water molecules

Question 10

Reduction

Answer 10

Adding a hydrogen, gaining an electron

Question 11

Prodrug

Answer 11

Inactive form of a drug that is activated

Question 12

Glucoronidation

Answer 12

Addition of glucoronide conjugates that makes molecules water soluble

Question 13

Polymorphisms in CYP

Answer 13

Extremely rapid metabolism of a drug or toxic effects from decreased metabolism

Question 14

Cat Phase II Metabolism

Answer 14

Low concentrations of glucoronyl transferases prolongs clearance of drugs

Question 15

Cat Phase I Metabolism

Answer 15

Deficiency in phase I demethylation and hydroxylation

Question 16

Acetamenophan in Cats

Answer 16

Excess shunted back to phase I metabolism, producing oxygen radicals that cause liver and RBC damage

Question 17

Sulfate Conjugating System

Answer 17

Alternative pathway to glucoronylation

Question 18

Acetylation

Answer 18

Less common route of xenobiotics, deficiency in dogs can change dosing of parent drugs

Question 19

Factors affecting metabolism

Answer 19

Activity of enzymes, hepatic blood flow, species, age, nutrition, tissue storage, health

Question 20

Flavonoids

Answer 20

Found in grapefruit, inhibits CYP in small intestine

Question 21

Ginkgo biloba

Answer 21

Induces CYP

Question 22

Young animal metabolism

Answer 22

Lower oxidative enzymes, liver enzymes developed at 3 months

Question 23

Hyperthyroid metabolism

Answer 23

Increased metabolic rate

Question 24

Hypothyroid metabolism

Answer 24

Decreased drug metabolism

Question 25

Drug interactions

Answer 25

Expect interactions when introducing multiple drugs metabolized by the liver

Question 26

CYP Induction

Answer 26

Protective mechanism that facilitates excretion of toxic compounds, however toxic metabolites will accumulate in the liver

Question 27

Type of Inhibitors

Answer 27

Reversible, quasireversible, and irreversible

Question 28

Drug induced metabolism inhibition

Answer 28

Can decrease dosage needed and prevent metabolism to toxic metabolites